Photosensitizer KillerRed

- Genetically-encoded photosensitizer, direct expression in cells
- No exogenous chemical compounds or cofactors required
- No cell toxicity before light activation
- Induction by green light irradiation
- Successful performance in fusions
- Recommended for selective in vivo cell killing and CALI applications

Available variants and fusions

KillerRed id developed on the basis of the chromoprotein from Anthomedusae sp.[Shagin et al., 2004]. Its codon usage is optimized for high expression in mammalian cells [Haas et al., 1996], but it can be successfully expressed in other heterological systems.

KillerRed-dMito fusion: Mitochondrial targeting sequence (MTS) was derived from subunit VIII precursor of human cytochrome C oxidase [Rizzuto et al., 1989; Rizzuto et al., 1995]. Two MTS were fused to KillerRed N-terminus. When expressed in mammalian cells, this variant is localized in mitochondria. Mitochondrial localization of KillerRed increases its light-induced cell toxity and makes it effective for cell killing presumably through apoptotic pathway.

KillerRed-mem fusion comprises KillerRed linked with membrane localization signal (MLS) of neuromodulin. The neuromodulin MLS (N-terminal 20 amino acid residues) contains a signal for posttranslational palmitoylation of cysteines 3 and 4 that targets KillerRed to cellular membranes [Skene and Virag, 1989]. Irradiation of membrane-localized KillerRed leads to high effective and fast cell death, presumably due to lipid oxidation. Comparing to the mitochondrially targeted KillerRed, irradiation of membrane-localized KillerRed leads to even more effective and fast cell death (within 10-30 min). Membrane-targeted KillerRed was shown to be suitable for the light induced cell killing within a developing zebrafish.